What is Space Weather? It can make even the most
destructive tornado here on Earth look like a gentle breeze. Eruptions from
the Sun, the disturbances in the solar wind, and the twisting and stretching
of Earth's magnetic field: collectively, we call it space weather. And, just
like weather here on Earth, it can be both mild-and wild.

A view of the Aurora Australis -- the Southern Lights --
taken from the Space Shuttle Discovery in 1991. The tail of the
shuttle can be seen to the left.
Photo courtesy of NASA.

Everyone is familiar with changes in the weather on Earth such as rain,
snow or a powerful hurricane. But faraway changes on the Sun and in
Earth's
magnetosphere
can cause another sort of weather that can effect
life on Earth: Space Weather.

There are four realms in our Sun-Earth Environment:

A powerhouse of energy and the source of the solar wind roaring through space

Full of charged particles and plasma spread by solar wind, marked by invisible magnetic fields.

A giant magnetic field surrounds Earth, pushed out of shape by the powerful solar wind.

Layers of air shield us from killer rays and solar wind, but magnetic storms and the aurora prove there's contact

Stormy Weather: The Sun-Earth Connection

Just as it effects weather on Earth, the Sun is responsible for
disturbances in our space environment as well.

Besides emitting a continuous stream of
plasma
called the
solar wind, the
Sun periodically releases billions of tons of matter in what are called
coronal mass ejections
. These immense clouds of material, when directed
towards Earth, can cause large
magnetic storms
in the magnetosphere and the
upper atmosphere.

Magnetic storms produce huge amounts of power - several million megawatts - more
than enough to power the United States. Magnetic storms are a series of
geospace
disturbances -- namely,
auroral
activity, increase in the
radiation levels in the inner magnetosphere, and rapid changes in Earth's
magnetic field -- caused by increased energy input from the solar wind.